Method of RFIC die-package configuration

ABSTRACT

A method for packaging a radio frequency integrated circuit (RFIC) in multiple packages begins by determining a 1 st  position of the RFIC die in a 1 st  package wherein the positioning is such to minimize adverse affects of parasitic components of coupling between the radio frequency input/output section and an antenna. Once the position within the 1 st  package has been determined, the corresponding parasitics are measured to determine their values. The processing then continues by determining a 2 nd  position of the RFIC die in a 2 nd  package based on the values of the parasitic components. Accordingly, the 2 nd  position places the die within the 2 nd  package such that the parasitic components of coupling between the RF I/O section to the antenna within the 2 nd  package substantially matches the parasitic components of coupling the RFIO section to the antenna in the 1 st  package. Accordingly, different packages may be used with the same RFIC die, while maintaining the desired noise reduction.

This patent application is claiming priority under 35 USC § 120 and 121as a divisional patent application of patent application entitled RFICDIE-PACKAGE CONFIGURATION, having a Ser. No. of 10/702,402 (now issuedU.S. Pat. No. 6,998,709), and a filing date of Nov. 5, 03.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to wireless communication devices andmore particularly to radio frequency integrated circuits used withinsuch wireless communication devices.

2. Description of Related Art

Communication systems are known to support wireless and wire linedcommunications between wireless and/or wire lined communication devices.Such communication systems range from national and/or internationalcellular telephone systems to the Internet to point-to-point in-homewireless networks. Each type of communication system is constructed, andhence operates, in accordance with one or more communication standards.For instance, wireless communication systems may operate in accordancewith one or more standards including, but not limited to, IEEE 802.11,Bluetooth, advanced mobile phone services (AMPS), digital AMPS, globalsystem for mobile communications (GSM), code division multiple access(CDMA), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), and/or variationsthereof.

Depending on the type of wireless communication system, a wirelesscommunication device, such as a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, et cetera communicates directlyor indirectly with other wireless communication devices. For directcommunications (also known as point-to-point communications), theparticipating wireless communication devices tune their receivers andtransmitters to the same channel or channels (e.g., one of the pluralityof radio frequency (RF) carriers of the wireless communication system)and communicate over that channel(s). For indirect wirelesscommunications, each wireless communication device communicates directlywith an associated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe Internet, and/or via some other wide area network.

For each wireless communication device to participate in wirelesscommunications, it includes a built-in radio transceiver (i.e., receiverand transmitter) or is coupled to an associated radio transceiver (e.g.,a station for in-home and/or in-building wireless communicationnetworks, RF modem, etc.). As is known, the transmitter includes a datamodulation stage, one or more intermediate frequency stages, and a poweramplifier. The data modulation stage converts raw data into basebandsignals in accordance with a particular wireless communication standard.The one or more intermediate frequency stages mix the baseband signalswith one or more local oscillations to produce RF signals. The poweramplifier amplifies the RF signals prior to transmission via an antenna.

As is also known, the receiver is coupled to the antenna and includes alow noise amplifier, one or more intermediate frequency stages, afiltering stage, and a data recovery stage. The low noise amplifierreceives inbound RF signals via the antenna and amplifies then. The oneor more intermediate frequency stages mix the amplified RF signals withone or more local oscillations to convert the amplified RF signal intobaseband signals or intermediate frequency (IF) signals. The filteringstage filters the baseband signals or the IF signals to attenuateunwanted out of band signals to produce filtered signals. The datarecovery stage recovers raw data from the filtered signals in accordancewith the particular wireless communication standard.

A critical issue with any mixed signal circuit, including radiotransceivers, is minimizing noise, especially at the sensitive pointswithin the mixed signal circuitry. In radio transceivers, one sensitivepoint is the receiver input that receives radio frequency (RF) signalsfrom an antenna. To minimize noise sensitivity, a receiver inputincludes a low noise amplifier to receive and subsequently amplifyincoming RF signals. Further, most low noise amplifiers are designed tohave an input impedance to substantially match the impedance of theantenna at radio frequencies. Alternatively, the receiver may include animpedance matching circuit between the antenna and low noise amplifierto provide the desired impedance matching.

When the RF transceiver is implemented as an integrated circuit, itincludes a die mounted within a package. The packages die (i.e., theintegrated circuit) is then mounted on a printed circuit board, whichincludes the antenna. Conventional packaging of the die may be doneusing commercial packages (e.g., ball grid array (BGA), LPCC, et cetera)where the die is placed in the center of the package. While suchpackaging has provided adequate performance in the past, as radiofrequencies increase and/or the data throughput demands increase, suchconventional packaging provides unacceptable levels of parasiticcomponents (e.g., capacitance and/or inductance). Such parasiticsincrease the noise levels of the radio frequency integrated circuit,degrade the input signal to the radio receiver, degrade output power ofthe radio transmitter, and thus limit the radio transceiver's overallperformance.

Therefore, a need exists for a radio frequency integrated circuit diepackaging configuration that minimizes adverse affects of packagingparasitics.

BRIEF SUMMARY OF THE INVENTION

The radio frequency integrated circuit (RFIC) die-package configurationof the present invention substantially meets these needs and others. Inone embodiment, a method for packaging a radio frequency integratedcircuit (RFIC) in multiple packages begins by determining a 1^(st)position of the RFIC die in a 1^(st) package wherein the positioning issuch to minimize adverse affects of parasitic components of couplingbetween the radio frequency input/output section and an antenna. Oncethe position within the 1^(st) package has been determined, thecorresponding parasitics are measured to determine their values. Theprocessing then continues by determining a 2^(nd) position of the RFICdie in a 2^(nd) package based on the values of the parasitic components.Accordingly, the 2^(nd) position places the die within the 2^(nd)package such that the parasitic components of coupling between the RFI/O section to the antenna within the 2^(nd) package substantiallymatches the parasitic components of coupling the RFIO section to theantenna in the 1^(st) package. Accordingly, different packages may beused with the same RFIC die, while maintaining the desired noisereduction.

In another embodiment, a radio frequency integrated circuit (RFIC)includes a die, and a package. In this embodiment, the die includes aradio frequency input/output (RF I/O) section, a radio frequency tobaseband conversion section and a baseband processing section. Thepackaging includes a ball grid array and an antenna. The antenna islocated on one edge of the package. Solder balls of the ball grid arrayproximal to the antenna are used to couple the RF I/O section of the dieto the antenna. By minimizing the trace length of coupling between theRF I/O section of the die and the antenna, the parasitic components arereduced thereby improving overall radio transceiver performance.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a wireless communication systemin accordance with the present invention;

FIG. 2 is a schematic block diagram of a wireless communication devicein accordance with the present invention;

FIG. 3 is a graphical representation of a radio frequency integratedcircuit in accordance with the present invention;

FIG. 4 is a graphical representation of coupling a die to an antenna inaccordance with the present invention;

FIG. 5 is a cross-sectional side view of the coupling illustrated inFIG. 4;

FIG. 6 is an alternate graphical representation of coupling a die to anantenna in accordance with the present invention; and

FIG. 7 is a logic diagram of a method for multiple packaging of a radiofrequency integrated circuit in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram illustrating a communication system10 that includes a plurality of base stations and/or access points12-16, a plurality of wireless communication devices 18-32 and a networkhardware component 34. The wireless communication devices 18-32 may belaptop host computers 18 and 26, personal digital assistant hosts 20 and30, personal computer hosts 24 and 32 and/or cellular telephone hosts 22and 28. The details of the wireless communication devices will bedescribed in greater detail with reference to FIG. 2.

The base stations or access points 12-16 are operably coupled to thenetwork hardware 34 via local area network connections 36, 38 and 40.The network hardware 34, which may be a router, switch, bridge, modem,system controller, et cetera provides a wide area network connection 42for the communication system 10. Each of the base stations or accesspoints 12-16 has an associated antenna or antenna array to communicatewith the wireless communication devices in its area. Typically, thewireless communication devices register with a particular base stationor access point 12-14 to receive services from the communication system10. For direct connections (i.e., point-to-point communications),wireless communication devices communicate directly via an allocatedchannel.

Typically, base stations are used for cellular telephone systems andlike-type systems, while access points are used for in-home orin-building wireless networks. Regardless of the particular type ofcommunication system, each wireless communication device includes abuilt-in radio and/or is coupled to a radio. The radio includes a highlylinear amplifier and/or programmable multi-stage amplifier as disclosedherein to enhance performance, reduce costs, reduce size, and/or enhancebroadband applications.

FIG. 2 is a schematic block diagram illustrating a wirelesscommunication device that includes the host device 18-32 and anassociated radio 60. For cellular telephone hosts, the radio 60 is abuilt-in component. For personal digital assistants hosts, laptop hosts,and/or personal computer hosts, the radio 60 may be built-in or anexternally coupled component.

As illustrated, the host device 18-32 includes a processing module 50,memory 52, radio interface 54, input interface 58 and output interface56. The processing module 50 and memory 52 execute the correspondinginstructions that are typically done by the host device. For example,for a cellular telephone host device, the processing module 50 performsthe corresponding communication functions in accordance with aparticular cellular telephone standard.

The radio interface 54 allows data to be received from and sent to theradio 60. For data received from the radio 60 (e.g., inbound data), theradio interface 54 provides the data to the processing module 50 forfurther processing and/or routing to the output interface 56. The outputinterface 56 provides connectivity to an output display device such as adisplay, monitor, speakers, et cetera such that the received data may bedisplayed. The radio interface 54 also provides data from the processingmodule 50 to the radio 60. The processing module 50 may receive theoutbound data from an input device such as a keyboard, keypad,microphone, et cetera via the input interface 58 or generate the dataitself. For data received via the input interface 58, the processingmodule 50 may perform a corresponding host function on the data and/orroute it to the radio 60 via the radio interface 54.

Radio 60 includes a host interface 62, digital receiver processingmodule 64, an analog-to-digital converter 66, a filtering/gain module68, an IF mixing down conversion stage 70, a receiver filter 71, a lownoise amplifier 72, a transmitter/receiver switch 73, a localoscillation module 74, memory 75, a digital transmitter processingmodule 76, a digital-to-analog converter 78, a filtering/gain module 80,an IF mixing up conversion stage 82, a power amplifier 84, a transmitterfilter module 85, and an antenna 86. The antenna 86 may be a singleantenna that is shared by the transmit and receive paths as regulated bythe Tx/Rx switch 73, or may include separate antennas for the transmitpath and receive path. The antenna implementation will depend on theparticular standard to which the wireless communication device iscompliant.

The digital receiver processing module 64 and the digital transmitterprocessing module 76, in combination with operational instructionsstored in memory 75, execute digital receiver functions and digitaltransmitter functions, respectively. The digital receiver functionsinclude, but are not limited to, digital intermediate frequency tobaseband conversion, demodulation, constellation demapping, decoding,and/or descrambling. The digital transmitter functions include, but arenot limited to, scrambling, encoding, constellation mapping, modulation,and/or digital baseband to IF conversion. The digital receiver andtransmitter processing modules 64 and 76 may be implemented using ashared processing device, individual processing devices, or a pluralityof processing devices. Such a processing device may be a microprocessor,micro-controller, digital signal processor, microcomputer, centralprocessing unit, field programmable gate array, programmable logicdevice, state machine, logic circuitry, analog circuitry, digitalcircuitry, and/or any device that manipulates signals (analog and/ordigital) based on operational instructions. The memory 75 may be asingle memory device or a plurality of memory devices. Such a memorydevice may be a read-only memory, random access memory, volatile memory,non-volatile memory, static memory, dynamic memory, flash memory, and/orany device that stores digital information. Note that when theprocessing module 64 and/or 76 implements one or more of its functionsvia a state machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory storing the corresponding operational instructionsis embedded with the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry.

In operation, the radio 60 receives outbound data 94 from the hostdevice via the host interface 62. The host interface 62 routes theoutbound data 94 to the digital transmitter processing module 76, whichprocesses the outbound data 94 in accordance with a particular wirelesscommunication standard (e.g., IEEE 802.11 Bluetooth, et cetera) toproduce digital transmission formatted data 96. The digital transmissionformatted data 96 will be a digital base-band signal or a digital low IFsignal, where the low IF typically will be in the frequency range of onehundred kilohertz to a few megahertz.

The digital-to-analog converter 78 converts the digital transmissionformatted data 96 from the digital domain to the analog domain. Thefiltering/gain module 80 filters and/or adjusts the gain of the analogsignal prior to providing it to the IF mixing stage 82. The IF mixingstage 82 converts the analog baseband or low IF signal into an RF signalbased on a transmitter local oscillation 83 provided by localoscillation module 74. The power amplifier 84 amplifies the RF signal toproduce outbound RF signal 98, which is filtered by the transmitterfilter module 85. The antenna 86 transmits the outbound RF signal 98 toa targeted device such as a base station, an access point and/or anotherwireless communication device.

The radio 60 also receives an inbound RF signal 88 via the antenna 86,which was transmitted by a base station, an access point, or anotherwireless communication device. The antenna 86 provides the inbound RFsignal 88 to the receiver filter module 71 via the Tx/Rx switch 73,where the Rx filter 71 bandpass filters the inbound RF signal 88. The Rxfilter 71 provides the filtered RF signal to low noise amplifier 72,which amplifies the signal 88 to produce an amplified inbound RF signal.The low noise amplifier 72 provides the amplified inbound RF signal tothe IF mixing module 70, which directly converts the amplified inboundRF signal into an inbound low IF signal or baseband signal based on areceiver local oscillation 81 provided by local oscillation module 74.The down conversion module 70 provides the inbound low IF signal orbaseband signal to the filtering/gain module 68. The filtering/gainmodule 68 filters and/or gains the inbound low IF signal or the inboundbaseband signal to produce a filtered inbound signal.

The analog-to-digital converter 66 converts the filtered inbound signalfrom the analog domain to the digital domain to produce digitalreception formatted data 90. The digital receiver processing module 64decodes, descrambles, demaps, and/or demodulates the digital receptionformatted data 90 to recapture inbound data 92 in accordance with theparticular wireless communication standard being implemented by radio60. The host interface 62 provides the recaptured inbound data 92 to thehost device 18-32 via the radio interface 54.

As one of average skill in the art will appreciate, the wirelesscommunication device of FIG. 2 may be implemented using one or moreintegrated circuits. For example, the host device may be implemented onone integrated circuit, the digital receiver processing module 64, thedigital transmitter processing module 76 and memory 75 may beimplemented on a second integrated circuit, and the remaining componentsof the radio 60, less the antenna 86, may be implemented on a thirdintegrated circuit. As an alternate example, the radio 60 may beimplemented on a single integrated circuit. As yet another example, theprocessing module 50 of the host device and the digital receiver andtransmitter processing modules 64 and 76 may be a common processingdevice implemented on a single integrated circuit. Further, the memory52 and memory 75 may be implemented on a single integrated circuitand/or on the same integrated circuit as the common processing modulesof processing module 50 and the digital receiver and transmitterprocessing module 64 and 76.

FIG. 3 is a graphical representation of a radio frequency integratedcircuit (RFIC) that includes a die 100, and a package 108. The die 100includes a radio frequency I/O (RFIO) section 102, a radio frequency tobaseband conversion section 104 and a baseband processing section 106.With reference to FIG. 2, the RFIO section 102 includes the low noiseamplifier 72, the receiver filter module 71, the T/R switch module 73,the transmit filter module 85, and the power amplifier 84. The RF tobaseband conversion section 104, with reference to FIG. 2, includes thedown conversion module 70, filter/gain module 68, analog-to-digitalconverter 66, digital-to-analog converter 78, filter/gain module 80,up-conversion module 82 and local oscillation module 74. The basebandprocessing section 106, with reference to FIG. 2, includes the digitalreceiver processing module 64, memory 75 and digital transmitterprocessing module 76.

Returning to the discussion of FIG. 2, the package 108 includes aplurality of connections 110, which may include a ball grid array or thepackage may be an LPCC. In any configuration of the package 108, the die100 is positioned to minimize the trace connection from the RFIO section102 to the antenna 112. In this embodiment, the antenna 112 is mountedand/or fabricated on a printed circuit board (PCB) which is coupled viaPCB traces 114 to the RF I/O section 102. Note that the die isoff-centered with respect to the package 108 to provide the minimaldistance coupling between the RF I/O section 102 and antenna 112.Remaining connections for the baseband processing section 106 mayinclude longer traces within package 108 to interconnecting solder ballsand/or pins of the package to the PCB without adversely affecting theoverall performance of the RFIC. Accordingly, by minimizing the distancebetween the RF I/O section 102 and the antenna 112, the correspondingparasitics that are produced by the printed circuit board trace 114, thecoupling of the die 100 to the package 108, and the coupling of thepackage 108 to the printed circuit board traces 114 are minimized suchthat at radio frequencies (e.g., 2.4 gigahertz, 5.25 gigahertz), theparasitics have negligible affect on the performance of the radiofrequency integrated circuit.

FIG. 4 is a more detailed graphical representation of coupling the RFIOsection 102 of die 100 to antenna 112. In this embodiment, the pluralityof connections 110 includes a ball grid array 120. The solder balls ofthe ball grid array 120 closest to antenna 112 are used to couple the RFI/O section 102 to the package 108. Corresponding solder balls and/orpins of the package are then used to couple to PCB traces 114 to providethe connectivity to antenna 112. This is further illustrated in FIG. 5.

FIG. 5 illustrates a side view of the coupling illustrated in FIG. 4. Inthis illustration, solder ball connections 118 couple RF I/O section 102of die 100 to the package 108. Within the package 108 there are tracesand/or vias that couple to solder balls and/or pins on the oppositesurface of package 108. The other solder balls are then used to connectto the printed circuit board traces 114, which couple to the antenna112. Accordingly, a minimal distance between the RF I/O section 102 andthe antenna 112 may be obtained thereby minimizing the parasiticcomponents and the adverse affects on the performance of the RFIC.

FIG. 6 illustrates an alternate configuration of the RFIC. In thisconfiguration, the antenna 112 is fabricated on the package 108. The RFI/O section 102 of die 100 is connected via package traces 115 andcorresponding solder balls to the antenna 112 within the package. Assuch, the distance between the RF I/O section 102 and the antenna 112may be further reduced thereby further reducing the correspondingparasitics and minimizing the adverse affects caused thereby.

FIG. 7 is a logic diagram of a method for multiple packaging of a radiofrequency integrated circuit. The process begins at Step 130 where a1^(st) position of the RFIC die in a 1^(st) package (e.g., a ball gridarray package) is determined. The position is selected to minimizeadverse affects of parasitic components of the coupling between the RFIOsection of the die and an antenna as described above. Such couplingincludes the coupling of the die to the package and the coupling of thepackage to the antenna, which may be via traces of a printed circuitboard and/or traces within the package. The 1^(st) position may beoffset from center and may further be at an edge of the 1^(st) package.The parasitic components may include inductance and/or capacitance.

The process then proceeds to Step 132 where the values of the parasiticcomponents are determined. The process then proceeds to Step 134 where a2^(nd) position of the RFIC die within a 2^(nd) package (e.g., LPCC) isdetermined based on the values of the parasitic components. Thepositioning within the 2^(nd) die is selected such that the values ofthe parasitic components between the RF I/O section and the antennasubstantially match the values of the parasitic components of thecoupling between the RFIO section to the antenna in the 1^(st) package.

The process then proceeds to Step 136 where a determination is made asto whether the die will be packaged in the 1^(st) package or the 2^(nd)package. When packaged in the 1^(st) package, the process proceeds toStep 138 where the RFIC die is packaged within the 1^(st) package inaccordance with the 1^(st) position. If the die is to be packaged in the2^(nd) package, the process proceeds to Step 140 where the RFIC die ispackaged within the 2^(nd) package in accordance with the 2^(nd)position.

As one of average skill in the art will appreciate, the term“substantially” or “approximately”, as may be used herein, provides anindustry-accepted tolerance to its corresponding term. Such anindustry-accepted tolerance ranges from less than one percent to twentypercent and corresponds to, but is not limited to, component values,integrated circuit process variations, temperature variations, rise andfall times, and/or thermal noise. As one of average skill in the artwill further appreciate, the term “operably coupled”, as may be usedherein, includes direct coupling and indirect coupling via anothercomponent, element, circuit, or module where, for indirect coupling, theintervening component, element, circuit, or module does not modify theinformation of a signal but may adjust its current level, voltage level,and/or power level. As one of average skill in the art will alsoappreciate, inferred coupling (i.e., where one element is coupled toanother element by inference) includes direct and indirect couplingbetween two elements in the same manner as “operably coupled”. As one ofaverage skill in the art will further appreciate, the term “comparesfavorably”, as may be used herein, indicates that a comparison betweentwo or more elements, items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1.

The preceding discussion has presented a radio frequency integratedcircuit die/packaging configuration that substantially reduces theadverse affects caused by parasitic components of the coupling betweenan antenna and the RF input/output section of a radio frequencyintegrated circuit. As one of average skill in the art will appreciate,other embodiments may be derived from the teaching of the presentinvention without deviating from the scope of the claims.

1. A method for multiple packaging of a radio frequency integratedcircuit (RFIC) die, the method comprises: determining a first positionof the RFIC die in a first package to minimize adverse affects ofparasitic components of coupling between pins of the first package and aradio frequency (RF) input/output (I/O) section of the RFIC die;determining values of the parasitic components; and determining a secondposition of the RFIC die in a second package based on the values of theparasitic components such that parasitic components of coupling betweenpins of the second package and the RF I/O section substantially matchthe parasitic components of the coupling between the pins of the firstpackage and the RF I/O section.
 2. The method of claim 1 furthercomprises: packaging the RFIC die within the first package in accordancewith the first position.
 3. The method of claim 1 further comprises:packaging the RFIC die with the second package in accordance with thesecond position.
 4. The method of claim 1, wherein the determining thefirst position further comprises: determining the first position to bean offset from a center of the first package.
 5. The method of claim 1,wherein the determining the first position further comprises:determining the first position to be at an edge of the first package. 6.The method of claim 1, wherein the minimizing the adverse affects of theparasitic components of the coupling comprises reducing inductance ofcoupling between the RF I/O section and the pins of the first package.